Hydrophobic weather-resistant anti-reflection coating for flexible substrate and preparation method of hydrophobic weather-resistant anti-reflection coating
By preparing a hydrophobic and weather-resistant antireflective coating of mixed silica nanoparticles and cross-linking system on a flexible substrate, the problems of poor coating adhesion and insufficient weather resistance in the prior art are solved, and the high transmittance and hydrophobicity are improved, and the process is simple.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-03-25
- Publication Date
- 2026-05-15
AI Technical Summary
Existing antireflective coatings for flexible substrates are inadequate in terms of hydrophobicity and weather resistance, resulting in poor adhesion between the coating and the substrate, easy delamination, and a complicated preparation process.
A hydrophobic, weather-resistant, and antireflective coating was prepared on a flexible substrate using a mixed silica nanoparticle and cross-linking system, combined with perfluoroether and block copolymer, via an dip-coating method. This process included the preparation of silica nanoparticles, the formation of a cross-linking network, and the preparation of a modified composite sol, followed by heat treatment for curing.
It significantly improves the optical transmittance and hydrophobicity of flexible substrates, enhances weather resistance, and has a simple and low-cost process. The coating also exhibits stable performance under high accelerated stress testing.
Smart Images
Figure CN122037628A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of coating preparation technology, specifically a hydrophobic, weather-resistant, and antireflective coating for flexible substrates and its preparation method. Background Technology
[0002] With the rapid development of flexible electronics technology, flexible substrates (such as polyimide (PI), polyethylene terephthalate (PET), and polycarbonate (PC)) are increasingly widely used in flexible displays, flexible photovoltaics, and wearable devices due to their advantages of lightweight, bendability, and portability. The optical performance and surface protection performance of these flexible devices directly determine the user experience and service life. For example, flexible foldable screens need to simultaneously meet the requirements of high light transmittance to ensure display clarity, as well as hydrophobicity and resistance to bending and friction to avoid fingerprint residue and scratches; flexible photovoltaic modules need to improve light capture efficiency through anti-reflective coatings, while using hydrophobic properties to reduce rainwater and dust adhesion and lower maintenance costs.
[0003] Patent CN118276200A discloses a method for preparing an antireflective film for flexible display devices. The double-layer antireflective film prepared by means of acrylic resin, reactive diluent, photoinitiator and inorganic nanoparticles has a peak transmittance of 93% and a water contact angle of about 65°. Patent CN113387596A discloses a method for preparing a superhydrophobic antireflective film, which includes the following steps: an antireflective film coating composition is prepared by mixing acid-catalyzed nano-SiO2 sol and alkali-catalyzed nano-SiO2 sol. The antireflective film coating composition is used to form a SiO2 antireflective film on the surface of photovoltaic glass by dip-coating method. The film is modified by forming a polyfluorine hydrophobic film by vapor deposition. The obtained antireflective film has an average transmittance of more than 93% in the visible light range. However, the adhesion decreases after the heat treatment temperature is reduced, and the film formation effect on the flexible substrate is poor, resulting in functional failure.
[0004] Existing flexible substrate materials have low surface energy and strong chemical inertness, resulting in a lack of stable chemical bonding between the coating and the substrate, making them prone to delamination after long-term friction. Double-layer coating requires multiple pretreatments and curing processes, which are cumbersome and prone to peeling due to insufficient interlayer adhesion. Therefore, existing antireflective coating technologies suitable for flexible substrates still require further optimization in terms of coating structure design, surface state control, and interfacial bonding. Furthermore, there is still room for improvement in the environmental and mechanical stability of antireflective coatings based on the above control strategies. Summary of the Invention
[0005] To address the shortcomings in the hydrophobic properties and weather resistance of current flexible substrate coatings, this invention provides a hydrophobic, weather-resistant, and antireflective coating for flexible substrates and its preparation method.
[0006] To solve the above-mentioned technical problems, the present invention provides the following technical solution: A method for preparing a hydrophobic, weather-resistant, and antireflective coating for flexible substrates, the method comprising the following steps: (1) Preparation of silica nanoparticles: Silane monomer, alkaline catalyst, alcohol solvent and deionized water are mixed and reacted. After a certain reaction time, inorganic silica nanoparticles are obtained. (2) Preparation of silica crosslinking network: Silane monomer, acid catalyst, alcohol solvent and deionized water are mixed and reacted. After a certain reaction time, an inorganic silica crosslinking system is obtained. (3) The inorganic silica nanoparticles synthesized in steps (1) and (2) and the crosslinking system of inorganic silica are mixed and then mixed with perfluoroether to obtain a modified sol; The block copolymer, alcohol solvent and deionized water were then mixed to obtain a dispersion, and the dispersion was then mixed with the modified sol in a certain proportion to obtain the modified composite sol. (4) The modified composite sol prepared in step (3) is pulled onto a flexible substrate and then heat-treated to cure it to obtain a hydrophobic, weather-resistant, and antireflective coating.
[0007] As an example, the alkaline catalyst is selected from ammonia, triethylamine, tetramethylammonium hydroxide, tetraethylammonium hydroxide, and ammonium hydroxide.
[0008] As an example, the acid catalyst is selected from hydrochloric acid, sulfuric acid, acetic acid, or nitric acid.
[0009] As an example, the silane monomer is one of tetraethyl orthosilicate, methyltrimethoxysilane, and ethyltrimethoxysilane.
[0010] As an example, the alcohol solvent in steps (1), (2) and (3) is methanol, ethanol or isopropanol.
[0011] As an example, the reaction temperature in the preparation process of silica nanoparticles in step (1) is room temperature and the reaction time is 1 hour.
[0012] As an example, in step (2), the preparation of the silica crosslinked network is carried out by heating and stirring at 50-65°C for 1 hour.
[0013] As an example, in step (3), the inorganic silica nanoparticles and the crosslinked system of inorganic silica are mixed in a volume ratio of 1:10-20 to prepare a mixed silica system; The block copolymer is PEO-PPO-PEO, PEG-PPO-PEO, PEG-PVP-PEO, PAA-PMMA-PAA, PBO-PEO, or PDMS-PAA.
[0014] As an example, the lifting speed in step (4) is 1000-3000 μm / s, and the lifting is carried out at an ambient temperature of 30℃ and a relative humidity of 36-38%. The heat treatment curing temperature is 80-150℃, and the curing time is 60 minutes.
[0015] The flexible substrate prepared according to the above method has a hydrophobic and weather-resistant antireflective coating.
[0016] The present invention has the following beneficial effects: The present invention provides a method for preparing a hydrophobic, weather-resistant, and antireflective coating for flexible substrates. The method involves mixing acid-catalyzed inorganic silica nanoparticles and an alkali-catalyzed inorganic silica crosslinking system to prepare a mixed silica system. This system is then combined with a dispersion liquid and applied to the substrate of a flexible substrate, which significantly improves optical transmittance, hydrophobicity, and weather resistance.
[0017] The method for preparing a hydrophobic and weather-resistant antireflective coating on a flexible substrate provided by this invention is simple and easy to operate, requires no complex equipment, and has low material costs. Attached Figure Description
[0018] Figure 1 The image shows the transmittance curves before and after the High Accelerated Stress Test (HAST) of the hydrophobic and weather-resistant antireflective coating in Example 1, and the schematic diagram of the water contact angle after HAST. Figure 2 The image shows the transmittance curves before and after the High Accelerated Stress Test (HAST) of the hydrophobic and weather-resistant antireflective coating in Example 2, and the schematic diagram of the water contact angle after HAST. Figure 3 This is a schematic diagram of the water contact angle before and after the high accelerated stress test (HAST) of the hydrophobic and weather-resistant antireflective coating in Example 3; Figure 4 This is a schematic diagram of the water contact angle before and after the high accelerated stress test (HAST) of the hydrophobic and weather-resistant antireflective coating in Example 4; Figure 5 This is a schematic diagram showing the transmittance curves and water contact angle of the hydrophobic and weather-resistant antireflective coating before and after the High Accelerated Stress Test (HAST) in Example 5. Figure 6 This is a schematic diagram showing the transmittance curves and water contact angle after HAST of the hydrophobic and weather-resistant antireflective coating in Example 6. Figure 7 This is a schematic diagram of the water contact angle between the flexible substrate and the hydrophobic, weather-resistant, and antireflective coating used in Comparative Example 1 of the present invention. Figure 8 The light transmittance curve of the hydrophobic and weather-resistant antireflective coating of Comparative Example 2 of the present invention is shown. Figure 9 This is a graph showing the transmittance curves of the hydrophobic, weather-resistant, and antireflective coating of Comparative Example 3 of the present invention before and after high accelerated stress testing. Detailed Implementation
[0019] The technical solution of the present invention will be clearly and completely described below with reference to specific embodiments. Experimental methods in the following embodiments that do not specify specific conditions are generally performed under conventional conditions or conditions recommended by the manufacturer. All reagents and materials used in the following embodiments of the present invention are commercially available products. Unless otherwise stated, "room temperature" in this specification refers to 20±2℃.
[0020] Example 1 (1) Preparation of silica nanoparticles Add 20 ml of tetraethyl orthosilicate, 100 μl of ammonia (25-28%), 30 ml of ethanol, and 2 ml of deionized water to a beaker and stir at room temperature for 1 hour to allow the silane monomer tetraethyl orthosilicate to undergo complete hydrolysis-condensation, thereby obtaining inorganic silica nanoparticles.
[0021] (2) Preparation of silica cross-linked network Add 25 ml of tetraethyl orthosilicate, 40 μl of hydrochloric acid (36-38%), 30 ml of ethanol, and 2 ml of deionized water to a three-necked flask, heat and reflux at 50 °C for 1 h to allow the silane monomer tetraethyl orthosilicate to fully hydrolyze and condense, thus obtaining a crosslinked system of inorganic silica.
[0022] (3) Preparation of modified composite sol The inorganic silica nanoparticles synthesized in steps (1) and (2) and the crosslinking system of inorganic silica were mixed at a volume ratio of 1:12 to obtain a mixed silica system. Then, 5 μl of perfluoroether (PFPE) was directly added to the mixed silica system, wherein the molar ratio of TEOS to PFPE was 450:1. The mixture was stirred for 2 h to obtain a modified sol. 10.5 g of PEO-PPO-PEO block copolymer, 100 ml of ethanol, and 8 ml of deionized water were then mixed to obtain a dispersion. After thorough stirring at room temperature, the dispersion was added to the modified sol to obtain a modified composite sol, wherein the molar ratio of the block copolymer in the dispersion to TEOS in the modified sol was 8 × 10⁻⁶. −3 .
[0023] (4) Preparation of hydrophobic anti-reflective layer The flexible PET substrate was ultrasonically cleaned in sequence with detergent water, deionized water, ethanol, acetone and isopropanol. After the cleaned flexible substrate was treated with oxygen plasma for 5 minutes, it was then dipped and pulled once on the flexible substrate at an ambient temperature of 30°C and a relative humidity of 36% using the modified composite sol prepared in step (3) at a pulling speed of 2000 μm / s. The substrate was then thermally cured at 100°C for 60 minutes to obtain a hydrophobic, weather-resistant, and antireflective coating.
[0024] In this embodiment, the hydrophobic, weather-resistant, and antireflective composite coating prepared on a flexible substrate under an environment of 36% relative humidity has an average transmittance of 95.7% and a peak transmittance of 97.2% in the range of 400-1000nm. Figure 1 This embodiment shows the transmittance curves of the hydrophobic, weather-resistant, and antireflective coating before and after the High Accelerated Stress Test (HAST) and the water contact angle after HAST.
[0025] HAST is a high-accelerated stress test that simulates the changes in the coating's performance before and after in a humid and hot environment. Under high temperature, high humidity and high pressure conditions, the coating still maintains high permeability and hydrophobicity, and the performance before and after is not significantly different, indicating that the coating is a hydrophobic, weather-resistant and antireflective coating.
[0026] Example 2 (1) Preparation of silica nanoparticles Add 20 ml of tetraethyl orthosilicate, 50 μl of triethylamine (1.1 mol / L), 30 ml of ethanol, and 2 ml of deionized water to a beaker and stir at room temperature for 1 h to allow the silane monomer tetraethyl orthosilicate to undergo complete hydrolysis-condensation, thereby obtaining inorganic silica nanoparticles.
[0027] (2) Preparation of silica cross-linked network Add 32 ml of ethyltrimethoxysilane, 70 μl of nitric acid (65-68%), 30 ml of methanol, and 5 ml of deionized water to a three-necked flask, heat and reflux at 65 °C for 1 h to allow the silane monomer ethyltrimethoxysilane to undergo complete hydrolysis-condensation, thus obtaining a crosslinked system of inorganic silica.
[0028] (3) Preparation of modified composite sol The inorganic silica nanoparticles synthesized in steps (1) and (2) and the crosslinking system of inorganic silica were mixed at a volume ratio of 1:15 to obtain a mixed silica system. Then, 10 μl of perfluoroether (PFPE) was directly added to the mixed silica system, wherein the molar ratio of TEOS to PFPE was 750:1. The mixture was stirred for 2 h to obtain a modified sol. 4.5 g of PEG-PPO-PEO block copolymer, 80 ml of ethanol, and 5 ml of deionized water were mixed to obtain a dispersion. After thorough stirring at room temperature, the dispersion was added to the previously modified sol to obtain a modified composite sol, wherein the molar ratio of the block copolymer in the dispersion to TEOS in the modified sol was 8 × 10⁻⁶. −3 .
[0029] (4) Preparation of hydrophobic anti-reflective layer The flexible PET substrate was ultrasonically cleaned in sequence with detergent water, deionized water, ethanol, acetone and isopropanol. After the cleaned flexible substrate was treated with oxygen plasma for 10 min, it was then dipped and pulled once on the flexible substrate at an ambient temperature of 30℃ and a relative humidity of 38% using the modified composite sol prepared in step (3) at a pulling speed of 1000 μm / s. Subsequently, it was thermally cured at 120℃. After 60 min, a hydrophobic, weather-resistant and antireflective composite layer was obtained.
[0030] In this embodiment, the hydrophobic antireflective coating prepared on a flexible substrate under 38% relative humidity conditions was subjected to a test at 121°C, 100%RH, and 0.1MPa for 24 hours (high-temperature, high-humidity, and high-pressure environment for testing) (high-accelerated stress test, i.e., HAST). The average transmittance of the coating in the 400-1000nm range decreased by only 0.2%. Figure 2 The graphs show the transmittance curves before and after the High Accelerated Stress Test (HAST) of the hydrophobic and weather-resistant antireflective coating in this embodiment, as well as the water contact angle after HAST.
[0031] Example 3 (1) Preparation of silica nanoparticles Add 40 ml of tetraethyl orthosilicate, 150 μl of tetramethylammonium hydroxide (25 wt%), 30 ml of ethanol, and 2 ml of deionized water to a beaker and stir at room temperature for 1 h to allow the silane monomer tetraethyl orthosilicate to undergo complete hydrolysis-condensation, thereby obtaining inorganic silica nanoparticles.
[0032] (2) Preparation of silica cross-linked network Add 10 ml of tetraethyl orthosilicate, 1 ml of hydrochloric acid (36-38%), 30 ml of ethanol, and 1 ml of deionized water to a three-necked flask, heat and reflux at 65°C for 1 hour to allow the silane monomer tetraethyl orthosilicate to fully hydrolyze and condense, thus obtaining a crosslinked system of inorganic silica.
[0033] (3) Preparation of modified composite sol The inorganic silica nanoparticles synthesized in steps (1) and (2) and the crosslinking system of inorganic silica were mixed at a volume ratio of 1:10 to obtain a mixed silica system. Then, 15 μl of perfluoroether (PFPE) was directly added to the mixed silica system, wherein the molar ratio of TEOS to PFPE was 750:1. The mixture was stirred for 2 h to obtain a modified sol. 11 g of PEG-PVP-PEO block copolymer, 102 ml of ethanol, and 7.2 ml of deionized water were mixed to obtain a dispersion. After thorough stirring at room temperature, the dispersion was added to the modified sol to obtain a modified composite sol, wherein the molar ratio of the block copolymer in the dispersion to TEOS in the modified sol was 8 × 10⁻⁶. −3 .
[0034] (4) Preparation of hydrophobic anti-reflective layer The flexible PET substrate was ultrasonically cleaned sequentially with detergent water, deionized water, ethanol, acetone, and isopropanol. After cleaning, the flexible substrate was treated with oxygen plasma for 10 minutes. Then, at an ambient temperature of 30°C and a relative humidity of 36%, the modified nanosol prepared in step (3) was applied to the flexible substrate once using the dip-coating method at a speed of 3000 μm / s. Subsequently, it was thermally cured at 150°C for 60 minutes to obtain a hydrophobic, weather-resistant, and antireflective coating. Figure 3 This is a schematic diagram of the water contact angle before and after the high accelerated stress test (HAST) of the hydrophobic and weather-resistant antireflective coating in this embodiment.
[0035] Example 4 (1) Preparation of silica nanoparticles Add 40 ml of tetraethyl orthosilicate, 110 μl of tetraethylammonium hydroxide (25 wt%), 30 ml of isopropanol, and 2 ml of deionized water to a beaker and stir at room temperature for 1 h to allow the silane monomer tetraethyl orthosilicate to undergo complete hydrolysis-condensation, thereby obtaining inorganic silica nanoparticles.
[0036] (2) Preparation of silica cross-linked network Add 3.2 ml of methyltrimethoxysilane, 400 μl of acetic acid (99.5%), 40 ml of ethanol, and 500 μl of deionized water to a three-necked flask, heat and reflux at 65 °C for 1 h to allow the silane monomer tetraethyl orthosilicate to undergo complete hydrolysis-condensation, thus obtaining a crosslinked system of inorganic silica.
[0037] (3) Preparation of modified composite sol The inorganic silica nanoparticles synthesized in steps (1) and (2) and the crosslinking system of inorganic silica were mixed at a volume ratio of 1:10 to obtain a mixed silica system. Then, 15 μl of perfluoroether (PFPE) was directly added to the mixed silica system, and the mixture was stirred for 2 h to obtain a modified sol, wherein the molar ratio of TEOS to PFPE was 300:1. 5.4 g of PAA-PMMA-PAA block copolymer, 80 ml of ethanol, and 5 ml of deionized water were mixed to obtain a dispersion. After thorough stirring at room temperature, the dispersion was added to the previously modified sol to obtain a modified composite sol, wherein the molar ratio of the block copolymer in the dispersion to TEOS in the modified sol was 8 × 10⁻⁶. −3 .
[0038] (4) Preparation of hydrophobic anti-reflective layer The flexible PET substrate was ultrasonically cleaned in sequence with detergent water, deionized water, ethanol, acetone and isopropanol. After the cleaned flexible substrate was treated with oxygen plasma for 10 min, it was then dipped and pulled once on the flexible substrate at an ambient temperature of 30℃ and a relative humidity of 36% using the modified composite sol prepared in step (3) at a pulling speed of 2500 μm / s. The substrate was then thermally cured at 100℃ for 60 min to obtain a hydrophobic, weather-resistant, and antireflective coating.
[0039] In this embodiment, the hydrophobic and weather-resistant antireflective coating prepared on a flexible substrate under an environment of 36% relative humidity only reduced its contact angle by 2° after a 24-hour high accelerated stress test (HAST), and remained hydrophobic. Figure 4 This is a schematic diagram of the water contact angle of the hydrophobic, weather-resistant, and antireflective coating before and after the High Accelerated Stress Test (HAST) in this embodiment. Figure 4 The left image shows the water contact angle before the test, which is 107°, and the right image shows the water contact angle after the test, which is 105°.
[0040] Example 5 (1) Preparation of silica nanoparticles Add 30 ml of tetraethyl orthosilicate, 110 μl of ammonium hydroxide (25-28%), 40 ml of isopropanol, and 2 ml of deionized water to a beaker and stir at room temperature for 1 hour to allow the silane monomer tetraethyl orthosilicate to undergo complete hydrolysis-condensation, thereby obtaining inorganic silica nanoparticles.
[0041] (2) Preparation of silica cross-linked network Add 5 ml of tetraethyl orthosilicate, 500 μl of hydrochloric acid (36-38%), 40 ml of ethanol, and 400 μl of deionized water to a three-necked flask. Heat and reflux at 65 °C for 1 h to allow the silane monomer tetraethyl orthosilicate to undergo complete hydrolysis-condensation, thus obtaining a crosslinked system of inorganic silica.
[0042] (3) Preparation of modified composite sol The inorganic silica nanoparticles synthesized in steps (1) and (2) and the crosslinked system of inorganic silica were mixed at a volume ratio of 1:15 to obtain a mixed silica system. Then, 18 μl of perfluoroether (PFPE) was directly added to the mixed silica system, and the mixture was stirred for 2 h to obtain a modified sol, wherein the molar ratio of TEOS to PFPE was 300:1. 1.2 g of PBO-PEO block copolymer, 80 ml of isopropanol, and 3.6 ml of deionized water were then mixed to obtain a dispersion. After thorough stirring at room temperature, the dispersion was added to the previously modified sol to obtain a modified composite sol, wherein the molar ratio of the block copolymer in the dispersion to TEOS in the modified sol was 8 × 10⁻⁶. −3 .
[0043] (4) Preparation of hydrophobic anti-reflective layer The flexible PET substrate was ultrasonically cleaned in sequence with detergent water, deionized water, ethanol, acetone and isopropanol. After the cleaned flexible substrate was treated with oxygen plasma for 10 min, it was then dipped and pulled once on the flexible substrate at an ambient temperature of 30℃ and a relative humidity of 36% using the modified composite sol prepared in step (3) at a pulling speed of 2500 μm / s. Subsequently, it was thermally cured at 80℃. After 60 min, a hydrophobic, weather-resistant, and antireflective coating was obtained.
[0044] In this embodiment, the hydrophobic and weather-resistant antireflective coating prepared on a flexible substrate under an environment of 36% relative humidity has a contact angle of 108° and is hydrophobic. Figure 5 This is a schematic diagram of the transmittance curves of the hydrophobic and weather-resistant antireflective coating prepared in this embodiment before and after high accelerated stress test (HAST) and the water contact angle (107°) after HAST.
[0045] Example 6 (1) Preparation of silica nanoparticles Add 30 ml of tetraethyl orthosilicate, 110 μl of ammonium hydroxide (25-28%), 40 ml of isopropanol, and 2 ml of deionized water to a beaker and stir at room temperature for 1 hour to allow the silane monomer tetraethyl orthosilicate to undergo complete hydrolysis-condensation, thereby obtaining inorganic silica nanoparticles.
[0046] (2) Preparation of silica cross-linked network Add 4 ml of methyltriethoxysilane, 300 μl of sulfuric acid (95-98%), 40 ml of methanol, and 100 μl of deionized water to a three-necked flask, heat and reflux at 65 °C for 1 h to allow the silane monomer tetraethyl orthosilicate to undergo complete hydrolysis-condensation, thus obtaining a crosslinked system of inorganic silica.
[0047] (3) Preparation of modified composite sol The inorganic silica nanoparticles synthesized in steps (1) and (2) and the crosslinking system of inorganic silica were mixed at a volume ratio of 1:20 to obtain a mixed silica system. Then, 18 μl of perfluoroether (PFPE) was directly added to the mixed silica system, and the mixture was stirred for 2 h to obtain a modified sol, wherein the molar ratio of TEOS to PFPE was 450:1. 6.4 g of PDMS-PAA block copolymer, 80 ml of methanol, and 5 ml of deionized water were then mixed to obtain a dispersion. After thorough stirring at room temperature, the dispersion was added to the previously modified sol to obtain a modified composite sol, wherein the molar ratio of the block copolymer in the dispersion to TEOS in the modified sol was 8 × 10⁻⁶. −3 .
[0048] (4) Preparation of hydrophobic anti-reflective layer After the flexible substrate PI was ultrasonically cleaned with detergent water, deionized water, ethanol, acetone and isopropanol in sequence, the cleaned flexible substrate was treated with oxygen plasma for 10 min. Then, at an ambient temperature of 30℃ and a relative humidity of 36%, the modified composite sol prepared in step (3) was used to pull the flexible substrate once at a pulling speed of 2500 μm / s by dip-pull method. Then, it was thermally cured at 120℃. After 60 min, a hydrophobic and weather-resistant antireflective coating was obtained.
[0049] In this embodiment, the hydrophobic and weather-resistant antireflective coating prepared on a flexible substrate under an environment of 36% relative humidity has a contact angle of 110° and is hydrophobic. Figure 6 This is a schematic diagram showing the transmittance curves of the hydrophobic and weather-resistant antireflective coating prepared in this embodiment before and after high accelerated stress test (HAST) and the water contact angle (108°) after HAST.
[0050] Comparative Example 1 This comparative example is basically the same as Example 1, except that step (3) is different, i.e., no perfluoroether was added.
[0051] In this comparative example, the obtained hydrophobic and weather-resistant antireflective coating has a contact angle of less than 90° and is in a hydrophilic state. Figure 7 The flexible substrate PET used in this comparative example is ( Figure 7 (Left image) and schematic diagram of the water contact angle of the hydrophobic and weather-resistant antireflective coating (right).
[0052] Comparative Example 2 This comparative example is basically the same as Example 1, except that no block copolymer was added in step (3).
[0053] In this comparative example, the transmittance of the obtained hydrophobic and weather-resistant antireflective coating is similar to that of the blank substrate, with only a slight improvement. Figure 8 This is a light transmittance curve of the hydrophobic, weather-resistant, and antireflective coating in this comparative example.
[0054] Comparative Example 3 This comparative example is basically the same as Example 1, except that step (1) is omitted, i.e., silica nanoparticles are not prepared.
[0055] In this comparative example, the transmittance of the obtained hydrophobic and weather-resistant antireflective coating decreased significantly after undergoing the same high accelerated stress test (HAST), indicating poor weather resistance. Figure 9 This is a graph showing the transmittance of the hydrophobic, weather-resistant, and antireflective coating before and after the High Accelerated Stress Test (HAST) in this comparative example.
[0056] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.
Claims
1. A method for preparing a hydrophobic, weather-resistant, antireflective coating for flexible substrates, characterized in that, The preparation method includes the following steps: (1) Preparation of silica nanoparticles: Silane monomer, alkaline catalyst, alcohol solvent and deionized water are mixed and reacted. After a certain reaction time, inorganic silica nanoparticles are obtained. (2) Preparation of silica crosslinking network: Silane monomer, acid catalyst, alcohol solvent and deionized water are mixed and reacted. After a certain reaction time, an inorganic silica crosslinking system is obtained. (3) The inorganic silica nanoparticles synthesized in steps (1) and (2) and the crosslinking system of inorganic silica are mixed and then mixed with perfluoroether to obtain a modified sol; The block copolymer, alcohol solvent and deionized water were then mixed to obtain a dispersion, and the dispersion was then mixed with the modified sol in a certain proportion to obtain the modified composite sol. (4) The modified composite sol prepared in step (3) is pulled onto a flexible substrate and then heat-treated to cure it to obtain a hydrophobic, weather-resistant, and antireflective coating.
2. The method for preparing the hydrophobic, weather-resistant, and antireflective coating according to claim 1, characterized in that, The alkaline catalyst is selected from one of ammonia, triethylamine, tetramethylammonium hydroxide, tetraethylammonium hydroxide, and ammonium hydroxide.
3. The method for preparing the hydrophobic, weather-resistant, and antireflective coating according to claim 1, characterized in that, The acid catalyst is selected from hydrochloric acid, sulfuric acid, acetic acid, or nitric acid.
4. The method for preparing the hydrophobic, weather-resistant, and antireflective coating according to claim 1, characterized in that, The silane monomer is one of tetraethyl orthosilicate, methyltrimethoxysilane, and ethyltrimethoxysilane.
5. The method for preparing the hydrophobic, weather-resistant, and antireflective coating according to claim 1, characterized in that, The alcohol solvent in steps (1), (2) and (3) is methanol, ethanol or isopropanol.
6. The method for preparing the hydrophobic, weather-resistant, and antireflective coating according to claim 1, characterized in that, In step (1), the reaction temperature during the preparation of silica nanoparticles is room temperature and the reaction time is 1 hour.
7. The method for preparing the hydrophobic, weather-resistant, and antireflective coating according to claim 1, characterized in that, In step (2), the preparation of the silica crosslinked network is carried out by heating and stirring at 50-65℃ for 1 hour.
8. The method for preparing the hydrophobic, weather-resistant, and antireflective coating according to claim 1, characterized in that, In step (3), the inorganic silica nanoparticles and the crosslinking system of inorganic silica are mixed in a volume ratio of 1:10-20 to prepare a mixed silica system; The block copolymer is PEO-PPO-PEO, PEG-PPO-PEO, PEG-PVP-PEO, PAA-PMMA-PAA, PBO-PEO, or PDMS-PAA.
9. The method for preparing the hydrophobic, weather-resistant, and antireflective coating according to claim 1, characterized in that, The lifting speed in step (4) is 1000-3000 μm / s, and the lifting is carried out at an ambient temperature of 30℃ and a relative humidity of 36-38%. The heat treatment curing temperature is 80-150℃, and the curing time is 60 minutes.
10. A hydrophobic, weather-resistant, antireflective coating for flexible substrates, characterized in that, The hydrophobic, weather-resistant, and antireflective coating for flexible substrates is prepared by the preparation method according to any one of claims 1-9.